Let x be the the cost of the woolen shirt. Since the woolen shirt cost $25 more than a cotton shirt, the price of the cotton shirt can be express as
![x-25](https://img.qammunity.org/2023/formulas/mathematics/college/dpkobee708wnylbxlsf1lbfmsa9lt39z7n.png)
We know that 3 cotton shirts and a woolen shirt cost $145, then:
![3(x-25)+x=145](https://img.qammunity.org/2023/formulas/mathematics/high-school/dspmz9epod8jyt1b6t7lrcbt0zzgqtkrfr.png)
Solving for x, we have
![\begin{gathered} 3(x-25)+x=145 \\ 3x-75+x=145 \\ 4x=145+75 \\ 4x=220 \\ x=(220)/(4) \\ x=55 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/23yfnyqw35z6ut6lqewucbvrg7ownk6n1x.png)
Therefore, the woolen shirt cost $55.